The goal of the biostatistics and data management core is to provide comprehensive data management and statistical analysis services to enhance the quality of the data analysis across the projects and to realize efficiency through shared personnel and data systems. As described in more detail below, this core will offer a broad range of services and collaboration. Core members will serve as true collaborators, having already been involved in the design of each project. Core members will continue to be involved in all projects through assistance and advice regarding data collection, statistical analysis, summarizing the results, and manuscript preparation. The specific aims of the core are to provide the following services: 1. Biostatistics a. Advise on study design issues as the studies progress. b. Implement analytical methods defined in the project-specific proposals. c. Conduct interim analyses. d. Conduct final analyses and assist with preparation for and writing of final reports, abstracts, manuscripts, and future research proposals. e. Conduct exploratory analyses that may lead to generation of new hypotheses for follow-up projects. 2. Data Management a. Implement a data management framework to facilitate statistical analysis, by establishing interaction among the biostatisticians, data analysts, database programmers, and the data collection core. b. Determine project-specific data management requirements and refine those as needed. c. Design and implement procedures for sampling, enrolling, and tracking subjects, and tracking the flow of data through the various phases of the program. d. Design and implement procedures for input forms design and coding, data entry and validation, quality assurance, and reporting of data. e. Design, test, implement, and maintain database structures and application programs to support aims c and d above.